Aim: In recent years, there have been multiple reports of delayed leukoencephalopathy (DL) occurring after endovascular treatment for cerebral vascular lesions, with polyvinylpyrrolidone (PVP) identified as a contributing factor. Herein, we present a case of DL developing after coil embolization for an unruptured aneurysm, and following the implementation of measures, we subsequently performed repeat endovascular treatment. Case Report: A 65-year-old female with a history of bronchial asthma underwent coil embolization using the double catheter technique for the right internal carotid artery -anterior choroidal artery aneurysm. One month postoperatively, she developed DL accompanied by left hemiparesis, which improved with steroid pulse therapy. Investigation into the cause of DL revealed elevated anti-nuclear antibodies, leading to a diagnosis of Sjögren\'s syndrome and Hashimoto\'s disease. Additionally, metal patch testing yielded negative results. At the 1year follow-up, an enlargement of a known basilar top aneurysm prompted the decision to perform stent-assisted coil embolization. To prevent peripheral scattering of PVP during the procedure, the decision was made to perform all imaging along a different axis guided by a catheter. Despite complications such as stent thrombosis, with no reduction in contrast agent usage, imaging frequency, or surgical time compared to the initial treatment, DL did not manifest in the postoperative course. Conclusion: For the prevention of DL after endovascular treatment, from a procedural aspect, it is important to reduce the peripheral dispersal of PVP that occurs during treatment. Performing angiography during treatment from a separate axis catheter may be a useful strategy in preventing the development of DL.